1. Field of the Invention
The present invention is related to a novel structural design of multi-frequency helix antenna, and especially to a set of communication equipment such as a mobile phone which can get the function of multi-frequency with a simple helical coil structure.
2. Description of the Prior Art
It is the primary antenna type having a helical coil made from winding of a metal wire, diameter and material of the coil as well as the total length of such a helix antenna can influence the set functions thereof. However, such a helix antenna still is widely adopted and has a quite stable signal emitting and receiving structure. In meeting the requirement of modern communication equipment, such a helix antenna can get various resonance frequencies through different structural designs. For example, a helical coil can be provided in an external sleeve, and an adjusting member is extended in the external sleeve, extending length of the adjusting member determines its resonance frequency. However, such structure not only increases complexity of production, but also increases cost of production.
Thereby, there are various miniaturized and planar microstrip antennas being developed gradually. However, earlier microstrip antennas, such as are disclosed in U.S. Pat. Nos. 3,921,177 and 3,810,183, generally are made from round or rectangular thin metallic rods, dielectric substance is filled in the space between such an antenna and the grounding member. Such a microstrip antenna generally can only allow narrower bandwidth. U.S. patent application No. 07/695686 provides a polygonal helical microstrip antenna which is improved against the earlier microstrip antennas, the bandwidth thereof can approach that of a normal helix antenna with a constant impedance. But this microstrip antenna is disadvantageous in having quite a large diameter when in low frequency, and does not suit modern portable communication equipment such as mobile phones.
Pointing to this, U.S. patent application No. 07/798700 (Taiwan patent no.81108896) provides a smaller microstrip antenna of broadband. However, the helical antenna element thereof is provided on a grounding plate, and dielectric substance and bearing material of specific thickness are filled in the space between it and the plate; the antenna can hardly further be reduced, and its signal emitting and receiving function is inferior to that of a helix antenna.
The object of the present invention is to provide a multi-frequency helix antenna capable of getting the function of multi-frequency with a simple and low cost helical coil structure.
To get the above stated object, the present invention is provided with a helix antenna with a helical column having its diameter, material, pitch of circles as well as the total length thereof preset, and the top section thereof is changed in its extending direction to be oriented inwardly along the axis of the helical column of the helix antenna itself, i.e., a predetermined length from the end of the radially extending section is integrally bent orthogonally inwardly along the central axis of the helical column of the helix antenna itself to form the multi-frequency helix antenna.
In a practicable embodiment of the present invention, the antenna can be combined to an upper surface of a metallic receiving seat, a coating layer is added to the antenna by injection enveloping.
In another embodiment of the present invention, the receiving seat of the helix antenna having been assembled can be combined to a corresponding connecting hole on the top surface of a mobile phone by means of an insertion section thereof.
The present invention will be apparent in its novelty and other characteristics after reading the detailed description of the preferred embodiment thereof in reference to the accompanying drawings.